Mitie Landscapes: understanding the biodiversity value of Magnox nuclear power stations Amanda Flint 1 March 2023

Mitie Landscapes: understanding the biodiversity value of Magnox nuclear power stations

Why putting a measurable biodiversity value on nature makes for better business decisions.

Magnox nuclear power stations

The challenge: increasing biodiversity value

Many businesses understand the importance of increasing biodiversity value for habitats and species affected by their operations.

Magnox has recently made biodiversity a KPI for the company; as a result, ascertaining biodiversity baselines as well as reviewing and collating key opportunities to enhance biodiversity and mitigating risks associated with future planning requirements has become a quantifiable objective.

What’s more, The Environment Act 2021 requires all new developments in England to deliver at least a 10% net gain in biodiversity value from November 2023.

As part of its work to decommission the UK’s first generation of nuclear sites, Mitie PLC and Magnox Ltd asked Middlemarch to carry out an audit so they could identify the stockholding of habitats on 12 sites across the UK, including Sizewell A, Dungeness A, Chapelcross and Oldbury power stations.

The audit would detail important species that might be present, natural-capital baselines for each site and how to increase biodiversity, contributing to Magnox’s sustainability goals of nurturing biodiversity and acting on climate change.

Natural-capital baselines aim to collect data that can quantify the extent, condition and value to society of a particular area or ecosystem.

Our approach: baseline biodiversity value audit

Our starting point was to undertake ecological and landscape surveys to  provide our client with a natural capital baseline value for each Magnox nuclear power station site. This incorporates the following points:

  • A loading within the local catchment area for fertilisers such as such as nitrogen and phosphorous, the UK’s main pollutants of aquatic environments
  • The site’s value for carbon sequestration, including the storage potential for carbon dioxide within natural features such as woodland, peat and different soils
  • Nearby Sites of Statutory Regulation, and how local policies surrounding those sites might inform decisions about decommissioning, and
  • An assessment of the baseline value for Magnox’s habitats defined in terms of biodiversity units, which were introduced as part of the Environmental Act 2021.

Once completed, this assessment gives every habitat within the site a biodiversity value based on the strategic significance of the habitat and how rare it is (see image below).

To gather this information, a Middlemarch Principal Consultant undertook site surveys, supported by a Project Manager, the rest of the Biodiversity and Nature-Based Solutions team and Middlemarch’s GIS team.

Our findings were set out in three reports for each Magnox nuclear power plant site: a Preliminary Ecological Appraisal, an Ecosystem Services Baseline and an Eco-Landscape Report.

Magnox nuclear power stations

The outcome: better business decisions about biodiversity value at Dungeness A Power Station

We identified that Dungeness A site’s existing habitat assets could potentially have a biodiversity value worth many millions of pounds in terms of the current trading price for biodiversity units (i).

This is despite the fact that the site covers an area of more than 20 hectares, but only around half of that is open to habitats.

Similarly, we identified that Dungeness A site’s existing habitats are capable of storing more than 177 tonnes of carbon. This capability has a significant value in the form of credits when it comes to carbon trading and offsetting (ii).

Understanding the natural capital wrapped up in Dungeness and its habitats will lead to more informed decision-making about the future of the site.

Our survey work will also help the site manager operate the site more effectively, particularly with the aim of improving habitats for biodiversity and for nature.

Benefits: a cost-effective approach to boosting biodiversity value

Alongside this audit, our client also asked Middlemarch to identify a biodiversity offset for three decommissioning projects that are occurring on the site in 2023.

The initial plans for development on site would have reduced the amount of coastal vegetated shingle by -3.4 biodiversity units, a decrease within the proposed development area of approximately 35% of the baseline value.

If a suitable offset could not be identified within the larger Dungeness Magnox landholding, then the alternative would be to purchase a habitat offset, costing in the range of £50,000 to £120,000 at present prices.

Further projects: increasing biodiversity value to protect two rare species

Consultants from Middlemarch’s Nature-Based Solutions team identified that the required biodiversity offset could be achieved through biodiversity enhancements and new management practices within other areas of the larger Dungeness Magnox landholding.

Biodiversity Net Gain Principles state that any biodiversity units claimed must be deliverable over a minimum period of 30 years. As such, a Biodiversity Enhancement Management Plan (BEMP) was provided with long-term management proposals and scope for monitoring and reporting.

These proposals demonstrate that the intended values will indeed be achieved over a minimum 30-year period.

A particular focus of the BEMP was to enhance the vegetated shingle for two rare species that only occur within the Dungeness area.

Parts of the shingle will be enhanced to improve the habitat for Red Hemp-nettle (see gallery below). Other areas will be enhanced to accommodate wild carrot, the food source of the Sussex Emerald Moth (see gallery below).

As part of the Enhancement Management Plans, Middlemarch provided a delivery plan, as well as annual monitoring, reporting and reviewing procedures.

Going forward, these can be undertaken by Mitie personnel on the Dungeness A site to make sure that the planned biodiversity enhancements are delivered.

Find out more

(i) Click here to find out more about habitat or diversity credits.
(ii) Click here to find out more about carbon sequestration and storage.

Contact us

If you are facing a similar challenge, get in touch.